lisp/progmodes/hideif.el

   1 ;;; hide-ifdef-mode.el --- hides selected code within ifdef.
   2
   3 ;;; Copyright (C) 1988, 1994 Free Software Foundation, Inc.
   4
   5 ;; Author: Dan LaLiberte <liberte@a.cs.uiuc.edu>
   6 ;; Maintainer: FSF
   7 ;; Keywords: c, outlines
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software; you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation; either version 2, or (at your option)
  14 ;; any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs; see the file COPYING.  If not, write to
  23 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  24
  25 ;;; Commentary:
  26
  27 ;;; To initialize, toggle the hide-ifdef minor mode with
  28 ;;;
  29 ;;; M-x hide-ifdef-mode
  30 ;;;
  31 ;;; This will set up key bindings and call hide-ifdef-mode-hook if it
  32 ;;; has a value.  To explicitly hide ifdefs using a buffer-local
  33 ;;; define list (default empty), type
  34 ;;;
  35 ;;; M-x hide-ifdefs  or C-c h
  36 ;;;
  37 ;;; Hide-ifdef suppresses the display of code that the preprocessor wouldn't
  38 ;;; pass through.  The support of constant expressions in #if lines is
  39 ;;; limited to identifiers, parens, and the operators: &&, ||, !, and
  40 ;;; "defined".  Please extend this.
  41 ;;;
  42 ;;; The hidden code is marked by ellipses (...).  Be
  43 ;;; cautious when editing near ellipses, since the hidden text is
  44 ;;; still in the buffer, and you can move the point into it and modify
  45 ;;; text unawares.  If you don't want to see the ellipses, set
  46 ;;; selective-display-ellipses to nil.  But this can be dangerous.
  47 ;;; You can make your buffer read-only while hide-ifdef-hiding by setting
  48 ;;; hide-ifdef-read-only to a non-nil value.  You can toggle this
  49 ;;; variable with hide-ifdef-toggle-read-only (C-c C-q).
  50 ;;;
  51 ;;; You can undo the effect of hide-ifdefs by typing
  52 ;;;
  53 ;;; M-x show-ifdefs  or C-c s
  54 ;;;
  55 ;;; Use M-x hide-ifdef-define (C-c d) to define a symbol.
  56 ;;; Use M-x hide-ifdef-undef (C-c u) to undefine a symbol.
  57 ;;;
  58 ;;; If you define or undefine a symbol while hide-ifdef-mode is in effect,
  59 ;;; the display will be updated.  Only the define list for the current
  60 ;;; buffer will be affected.  You can save changes to the local define
  61 ;;; list with hide-ifdef-set-define-alist.  This adds entries
  62 ;;; to hide-ifdef-define-alist.
  63 ;;;
  64 ;;; If you have defined a hide-ifdef-mode-hook, you can set
  65 ;;; up a list of symbols that may be used by hide-ifdefs as in the
  66 ;;; following example:
  67 ;;;
  68 ;;; (setq hide-ifdef-mode-hook
  69 ;;;      '(lambda ()
  70 ;;;      (if (not hide-ifdef-define-alist)
  71 ;;;          (setq hide-ifdef-define-alist
  72 ;;;               '((list1 ONE TWO)
  73 ;;;                 (list2 TWO THREE)
  74 ;;;                 )))
  75 ;;;      (hide-ifdef-use-define-alist 'list2) ; use list2 by default
  76 ;;;      ))
  77 ;;;
  78 ;;; You can call hide-ifdef-use-define-alist (C-c u) at any time to specify
  79 ;;; another list to use.
  80 ;;;
  81 ;;; To cause ifdefs to be hidden as soon as hide-ifdef-mode is called,
  82 ;;; set hide-ifdef-initially to non-nil.
  83 ;;;
  84 ;;; If you set hide-ifdef-lines to t, hide-ifdefs hides all the #ifdef lines.
  85 ;;; In the absence of highlighting, that might be a bad idea.  If you set
  86 ;;; hide-ifdef-lines to nil (the default), the surrounding preprocessor
  87 ;;; lines will be displayed.  That can be confusing in its own
  88 ;;; right.  Other variations on display are possible, but not much
  89 ;;; better.
  90 ;;;
  91 ;;; You can explicitly hide or show individual ifdef blocks irrespective
  92 ;;; of the define list by using hide-ifdef-block and show-ifdef-block.
  93 ;;;
  94 ;;; You can move the point between ifdefs with forward-ifdef, backward-ifdef,
  95 ;;; up-ifdef, down-ifdef, next-ifdef, and previous-ifdef.
  96 ;;;
  97 ;;; If you have minor-mode-alist in your mode line (the default) two labels
  98 ;;; may appear.  "Ifdef" will appear when hide-ifdef-mode is active.  "Hiding"
  99 ;;; will appear when text may be hidden ("hide-ifdef-hiding" is non-nil).
 100 ;;;
 101 ;;; Written by Brian Marick, at Gould, Computer Systems Division, Urbana IL.
 102 ;;; Extensively modified by Daniel LaLiberte (while at Gould).
 103 ;;;
 104 ;;; You may freely modify and distribute this, but keep a record
 105 ;;; of modifications and send comments to:
 106 ;;;      liberte@a.cs.uiuc.edu  or  ihnp4!uiucdcs!liberte
 107 ;;; I will continue to upgrade hide-ifdef-mode
 108 ;;; with your contributions.
 109
 110 ;;; Code:
 111
 112 (defvar hide-ifdef-mode-submap nil
 113   "Keymap used with Hide-Ifdef mode.")
 114
 115 (defvar hide-ifdef-mode-map nil
 116   "Keymap used with Hide-Ifdef mode.")
 117
 118 (defconst hide-ifdef-mode-prefix-key "\C-c"
 119   "Prefix key for all Hide-Ifdef mode commands.")
 120
 121 ;; Set up the submap that goes after the prefix key.
 122 (if hide-ifdef-mode-submap
 123     ()                          ; dont redefine it.
 124   (setq hide-ifdef-mode-submap (make-sparse-keymap))
 125   (define-key hide-ifdef-mode-submap "\ed" 'hide-ifdef-define)
 126   (define-key hide-ifdef-mode-submap "\eu" 'hide-ifdef-undef)
 127   (define-key hide-ifdef-mode-submap "\eD" 'hide-ifdef-set-define-alist)
 128   (define-key hide-ifdef-mode-submap "\eU" 'hide-ifdef-use-define-alist)
 129
 130   (define-key hide-ifdef-mode-submap "\eh" 'hide-ifdefs)
 131   (define-key hide-ifdef-mode-submap "\es" 'show-ifdefs)
 132   (define-key hide-ifdef-mode-submap "\C-d" 'hide-ifdef-block)
 133   (define-key hide-ifdef-mode-submap "\C-s" 'show-ifdef-block)
 134
 135   (define-key hide-ifdef-mode-submap "\C-q" 'hide-ifdef-toggle-read-only)
 136   (let ((where (where-is-internal 'toggle-read-only '(keymap) t)))
 137     (if where
 138         (define-key hide-ifdef-mode-submap
 139           where
 140           'hide-ifdef-toggle-outside-read-only)))
 141   )
 142
 143 ;; Set up the mode's main map, which leads via the prefix key to the submap.
 144 (if hide-ifdef-mode-map
 145     ()
 146   (setq hide-ifdef-mode-map (make-sparse-keymap))
 147   (define-key hide-ifdef-mode-map hide-ifdef-mode-prefix-key
 148     hide-ifdef-mode-submap))
 149
 150 (defun hif-update-mode-line ()
 151   "Update mode-line by setting buffer-modified to itself."
 152   (set-buffer-modified-p (buffer-modified-p)))
 153
 154 (defvar hide-ifdef-mode nil
 155   "Non-nil when hide-ifdef-mode is activated.")
 156
 157 (defvar hide-ifdef-hiding nil
 158   "Non-nil when text may be hidden.")
 159
 160 ;; Arrange to use the mode's map when the mode is enabled.
 161 (or (assq 'hide-ifdef-mode minor-mode-map-alist)
 162     (setq minor-mode-map-alist
 163           (cons (cons 'hide-ifdef-mode hide-ifdef-mode-map)
 164                 minor-mode-map-alist)))
 165
 166 (or (assq 'hide-ifdef-hiding minor-mode-alist)
 167     (setq minor-mode-alist
 168           (cons '(hide-ifdef-hiding " Hiding")
 169                 minor-mode-alist)))
 170
 171 (or (assq 'hide-ifdef-mode minor-mode-alist)
 172     (setq minor-mode-alist
 173           (cons '(hide-ifdef-mode " Ifdef")
 174                 minor-mode-alist)))
 175
 176 ;; fix c-mode syntax table so we can recognize whole symbols.
 177 (defvar hide-ifdef-syntax-table
 178   (copy-syntax-table c-mode-syntax-table)
 179   "Syntax table used for tokenizing #if expressions.")
 180
 181 (modify-syntax-entry ?_ "w" hide-ifdef-syntax-table)
 182 (modify-syntax-entry ?& "." hide-ifdef-syntax-table)
 183 (modify-syntax-entry ?\| "." hide-ifdef-syntax-table)
 184
 185 ;;;###autoload
 186 (defun hide-ifdef-mode (arg)
 187   "Toggle Hide-Ifdef mode.  This is a minor mode, albeit a large one.
 188 With ARG, turn Hide-Ifdef mode on iff arg is positive.
 189 In Hide-Ifdef mode, code within #ifdef constructs that the C preprocessor
 190 would eliminate may be hidden from view.  Several variables affect
 191 how the hiding is done:
 192
 193 hide-ifdef-env
 194         An association list of defined and undefined symbols for the
 195         current buffer.  Initially, the global value of `hide-ifdef-env'
 196         is used.
 197
 198 hide-ifdef-define-alist
 199         An association list of defined symbol lists.
 200         Use `hide-ifdef-set-define-alist' to save the current `hide-ifdef-env'
 201         and `hide-ifdef-use-define-alist' to set the current `hide-ifdef-env'
 202         from one of the lists in `hide-ifdef-define-alist'.
 203
 204 hide-ifdef-lines
 205         Set to non-nil to not show #if, #ifdef, #ifndef, #else, and
 206         #endif lines when hiding.
 207
 208 hide-ifdef-initially
 209         Indicates whether `hide-ifdefs' should be called when Hide-Ifdef mode
 210         is activated.
 211
 212 hide-ifdef-read-only
 213         Set to non-nil if you want to make buffers read only while hiding.
 214         After `show-ifdefs', read-only status is restored to previous value.
 215
 216 \\{hide-ifdef-mode-map}"
 217
 218   (interactive "P")
 219   (make-local-variable 'hide-ifdef-mode)
 220   (setq hide-ifdef-mode
 221         (if (null arg)
 222             (not hide-ifdef-mode)
 223           (> (prefix-numeric-value arg) 0)))
 224
 225   (force-mode-line-update)
 226
 227   (if hide-ifdef-mode
 228       (progn
 229         ; inherit global values
 230         (make-local-variable 'hide-ifdef-env)
 231         (setq hide-ifdef-env (default-value 'hide-ifdef-env))
 232
 233         (make-local-variable 'hide-ifdef-hiding)
 234         (setq hide-ifdef-hiding (default-value 'hide-ifdef-hiding))
 235
 236         (make-local-variable 'hif-outside-read-only)
 237         (setq hif-outside-read-only buffer-read-only)
 238
 239         (run-hooks 'hide-ifdef-mode-hook)
 240
 241         (if hide-ifdef-initially
 242             (hide-ifdefs)
 243           (show-ifdefs))
 244         (message "Enter hide-ifdef-mode.")
 245         )
 246      ; else end hide-ifdef-mode
 247     (if hide-ifdef-hiding
 248         (show-ifdefs))
 249     (message "Exit hide-ifdef-mode.")
 250     ))
 251
 252
 253 ;; from outline.el with docstring fixed.
 254 (defun hif-outline-flag-region (from to flag)
 255   "Hides or shows lines from FROM to TO, according to FLAG.  If FLAG
 256 is \\n (newline character) then text is shown, while if FLAG is \\^M
 257 \(control-M) the text is hidden."
 258   (let ((modp (buffer-modified-p)))
 259     (unwind-protect (progn
 260                       (subst-char-in-region from to
 261                               (if (= flag ?\n) ?\^M ?\n)
 262                               flag t) )
 263       (set-buffer-modified-p modp))
 264     ))
 265
 266 (defun hif-show-all ()
 267   "Show all of the text in the current buffer."
 268   (interactive)
 269   (hif-outline-flag-region (point-min) (point-max) ?\n))
 270
 271 (defun hide-ifdef-region (start end)
 272   "START is the start of a #if or #else form.  END is the ending part.
 273 Everything including these lines is made invisible."
 274   (hif-outline-flag-region start end ?\^M)
 275   )
 276
 277 (defun hif-show-ifdef-region (start end)
 278   "Everything between START and END is made visible."
 279   (hif-outline-flag-region start end ?\n)
 280   )
 281
 282
 283
 284 ;===%%SF%% evaluation (Start)  ===
 285
 286 (defvar hide-ifdef-evaluator 'eval
 287   "The evaluator is given a canonical form and returns T if text under
 288 that form should be displayed.")
 289
 290 (defvar hif-undefined-symbol nil
 291   "...is by default considered to be false.")
 292
 293 (defvar hide-ifdef-env nil
 294   "An alist of defined symbols and their values.")
 295
 296
 297 (defun hif-set-var (var value)
 298   "Prepend (var value) pair to hide-ifdef-env."
 299   (setq hide-ifdef-env (cons (cons var value) hide-ifdef-env)))
 300
 301
 302 (defun hif-lookup (var)
 303 ;  (message "hif-lookup %s" var)
 304   (let ((val (assoc var hide-ifdef-env)))
 305     (if val
 306         (cdr val)
 307       hif-undefined-symbol)))
 308
 309 (defun hif-defined (var)
 310   (hif-lookup var)
 311   ; when #if expressions are fully supported, defined result should be 1
 312   ;  (if (assoc var  hide-ifdef-env)
 313   ;      1
 314   ;    nil)
 315 )
 316
 317
 318 ;===%%SF%% evaluation (End)  ===
 319
 320
 321
 322 ;===%%SF%% parsing (Start)  ===
 323 ;;;  The code that understands what ifs and ifdef in files look like.
 324
 325 (defconst hif-cpp-prefix "\\(^\\|\r\\)[ \t]*#[ \t]*")
 326 (defconst hif-ifndef-regexp (concat hif-cpp-prefix "ifndef"))
 327 (defconst hif-ifx-regexp (concat hif-cpp-prefix "if\\(n?def\\)?[ \t]+"))
 328 (defconst hif-else-regexp (concat hif-cpp-prefix "else"))
 329 (defconst hif-endif-regexp (concat hif-cpp-prefix "endif"))
 330 (defconst hif-ifx-else-endif-regexp
 331   (concat hif-ifx-regexp "\\|" hif-else-regexp "\\|" hif-endif-regexp))
 332
 333
 334 (defun hif-infix-to-prefix (token-list)
 335   "Convert list of tokens in infix into prefix list"
 336 ;  (message "hif-infix-to-prefix: %s" token-list)
 337   (if (= 1 (length token-list))
 338       (` (hif-lookup (quote (, (car token-list)))))
 339     (hif-parse-if-exp token-list))
 340   )
 341
 342 ; pattern to match initial identifier, !, &&, ||, (, or ).
 343 ; Added ==, + and -: garyo@avs.com 8/9/94
 344 (defconst hif-token-regexp "^\\(!\\|&&\\|||\\|[!=]=\\|[()+-]\\|\\w+\\)")
 345 (defconst hif-end-of-comment "\\*/")
 346
 347
 348 (defun hif-tokenize (expr-string)
 349   "Separate string into a list of tokens"
 350   (let ((token-list nil)
 351         (expr-start 0)
 352         (expr-length (length expr-string))
 353         (current-syntax-table (syntax-table)))
 354     (unwind-protect
 355         (progn
 356           (set-syntax-table hide-ifdef-syntax-table)
 357           (while (< expr-start expr-length)
 358 ;           (message "expr-start = %d" expr-start) (sit-for 1)
 359             (cond
 360              ((string-match "^[ \t]+" expr-string expr-start)
 361               ;; skip whitespace
 362               (setq expr-start (match-end 0))
 363               ;; stick newline in string so ^ matches on the next string-match
 364               (aset expr-string (1- expr-start) ?\n))
 365
 366              ((string-match "^/\\*" expr-string expr-start)
 367               (setq expr-start (match-end 0))
 368               (aset expr-string (1- expr-start) ?\n)
 369               (or
 370                (string-match hif-end-of-comment
 371                              expr-string expr-start) ; eat comment
 372                (string-match "$" expr-string expr-start)) ; multi-line comment
 373               (setq expr-start (match-end 0))
 374               (aset expr-string (1- expr-start) ?\n))
 375
 376              ((string-match "^//" expr-string expr-start)
 377               (string-match "$" expr-string expr-start)
 378               (setq expr-start (match-end 0)))
 379
 380              ((string-match hif-token-regexp expr-string expr-start)
 381               (let ((token (substring expr-string expr-start (match-end 0))))
 382                 (setq expr-start (match-end 0))
 383                 (aset expr-string (1- expr-start) ?\n)
 384 ;               (message "token: %s" token) (sit-for 1)
 385                 (setq token-list
 386                       (cons
 387                        (cond
 388                         ((string-equal token "||") 'or)
 389                         ((string-equal token "&&") 'and)
 390                         ((string-equal token "==") 'equal)
 391                         ((string-equal token "!=") 'hif-notequal)
 392                         ((string-equal token "!")  'not)
 393                         ((string-equal token "defined") 'hif-defined)
 394                         ((string-equal token "(") 'lparen)
 395                         ((string-equal token ")") 'rparen)
 396                         ((string-equal token "+") 'hif-plus)
 397                         ((string-equal token "-") 'hif-minus)
 398                         (t (intern token)))
 399                        token-list))))
 400              (t (error "Bad #if expression: %s" expr-string)))))
 401       (set-syntax-table current-syntax-table))
 402     (nreverse token-list)))
 403
 404 ;;;-----------------------------------------------------------------
 405 ;;; Translate C preprocessor #if expressions using recursive descent.
 406 ;;; This parser is limited to the operators &&, ||, !, and "defined".
 407 ;;; Added ==, !=, +, and -.  Gary Oberbrunner, garyo@avs.com, 8/9/94
 408
 409 (defun hif-parse-if-exp (token-list)
 410   "Parse the TOKEN-LIST.  Return translated list in prefix form."
 411   (hif-nexttoken)
 412   (prog1
 413       (hif-expr)
 414     (if token ; is there still a token?
 415         (error "Error: unexpected token: %s" token))))
 416
 417 (defun hif-nexttoken ()
 418   "Pop the next token from token-list into the let variable \"token\"."
 419   (setq token (car token-list))
 420   (setq token-list (cdr token-list))
 421   token)
 422
 423 (defun hif-expr ()
 424   "Parse and expression of the form
 425        expr : term | expr '||' term."
 426   (let ((result (hif-term)))
 427     (while (eq  token 'or)
 428       (hif-nexttoken)
 429       (setq result (list 'or result (hif-term))))
 430   result))
 431
 432 (defun hif-term ()
 433   "Parse a term of the form
 434        term : eq-expr | term '&&' eq-expr."
 435   (let ((result (hif-eq-expr)))
 436     (while (eq token 'and)
 437       (hif-nexttoken)
 438       (setq result (list 'and result (hif-eq-expr))))
 439     result))
 440
 441 (defun hif-eq-expr ()
 442   "Parse a term of the form
 443        eq-expr : math | eq-expr '=='|'!=' math."
 444   (let ((result (hif-math))
 445         (eq-token nil))
 446     (while (or (eq token 'equal) (eq token 'hif-notequal))
 447       (setq eq-token token)
 448       (hif-nexttoken)
 449       (setq result (list eq-token result (hif-math))))
 450     result))
 451
 452 (defun hif-math ()
 453   "Parse an expression of the form
 454        math : factor | math '+|-' factor."
 455   (let ((result (hif-factor))
 456         (math-op nil))
 457     (while (or (eq  token 'hif-plus) (eq token 'hif-minus))
 458       (setq math-op token)
 459       (hif-nexttoken)
 460       (setq result (list math-op result (hif-factor))))
 461   result))
 462
 463 (defun hif-factor ()
 464   "Parse a factor of the form
 465        factor : '!' factor | '(' expr ')' | 'defined(' id ')' | id."
 466   (cond
 467     ((eq token 'not)
 468      (hif-nexttoken)
 469      (list 'not (hif-factor)))
 470
 471     ((eq token 'lparen)
 472      (hif-nexttoken)
 473      (let ((result (hif-expr)))
 474        (if (not (eq token 'rparen))
 475            (error "Bad token in parenthesized expression: %s" token)
 476          (hif-nexttoken)
 477          result)))
 478
 479     ((eq token 'hif-defined)
 480      (hif-nexttoken)
 481      (if (not (eq token 'lparen))
 482          (error "Error: expected \"(\" after \"defined\""))
 483      (hif-nexttoken)
 484      (let ((ident token))
 485        (if (memq token '(or and not hif-defined lparen rparen))
 486            (error "Error: unexpected token: %s" token))
 487        (hif-nexttoken)
 488        (if (not (eq token 'rparen))
 489            (error "Error: expected \")\" after identifier"))
 490        (hif-nexttoken)
 491        (` (hif-defined (quote (, ident))))
 492        ))
 493
 494     (t ; identifier
 495       (let ((ident token))
 496         (if (memq ident '(or and))
 497             (error "Error: missing identifier"))
 498         (hif-nexttoken)
 499         (` (hif-lookup (quote (, ident))))
 500         ))
 501     ))
 502
 503 (defun hif-mathify (val)
 504   "Treat VAL as a number: if it's t or nil, use 1 or 0."
 505   (cond ((eq val t)
 506          1)
 507         ((null val)
 508          0)
 509         (t val)))
 510
 511 (defun hif-plus (a b)
 512   "Like ordinary plus but treat t and nil as 1 and 0."
 513   (+ (hif-mathify a) (hif-mathify b)))
 514 (defun hif-minus (a b)
 515   "Like ordinary minus but treat t and nil as 1 and 0."
 516   (- (hif-mathify a) (hif-mathify b)))
 517 (defun hif-notequal (a b)
 518   "Like (not (equal A B)) but as one symbol."
 519   (not (equal a b)))
 520
 521 ;;;----------- end of parser -----------------------
 522
 523
 524 (defun hif-canonicalize ()
 525   "When at beginning of #ifX, returns a canonical (evaluatable)
 526        form for the expression."
 527   (save-excursion
 528     (let ((negate (looking-at hif-ifndef-regexp)))
 529       (re-search-forward hif-ifx-regexp)
 530       (let* ((expr-string
 531               (buffer-substring (point)
 532                                 (progn (skip-chars-forward "^\n\r") (point))))
 533              (expr (hif-infix-to-prefix (hif-tokenize expr-string))))
 534 ;       (message "hif-canonicalized: %s" expr)
 535         (if negate
 536             (list 'not expr)
 537           expr)))))
 538
 539
 540 (defun hif-find-any-ifX ()
 541   "Position at beginning of next #if, #ifdef, or #ifndef, including one on
 542 this line."
 543 ;  (message "find ifX at %d" (point))
 544   (prog1
 545       (re-search-forward hif-ifx-regexp (point-max) t)
 546     (beginning-of-line)))
 547
 548
 549 (defun hif-find-next-relevant ()
 550   "Position at beginning of next #ifdef, #ifndef, #else, #endif,
 551 NOT including one on this line."
 552 ;  (message "hif-find-next-relevant at %d" (point))
 553   (end-of-line)
 554   ; avoid infinite recursion by only going to beginning of line if match found
 555   (if (re-search-forward hif-ifx-else-endif-regexp (point-max) t)
 556       (beginning-of-line)))
 557
 558 (defun hif-find-previous-relevant ()
 559   "Position at beginning of previous #ifdef, #ifndef, #else, #endif,
 560 NOT including one on this line."
 561 ;  (message "hif-find-previous-relevant at %d" (point))
 562   (beginning-of-line)
 563   ; avoid infinite recursion by only going to beginning of line if match found
 564   (if (re-search-backward hif-ifx-else-endif-regexp (point-min) t)
 565      (beginning-of-line)))
 566
 567
 568 (defun hif-looking-at-ifX ()            ;; Should eventually see #if
 569   (looking-at hif-ifx-regexp))
 570 (defun hif-looking-at-endif ()
 571   (looking-at hif-endif-regexp))
 572 (defun hif-looking-at-else ()
 573   (looking-at hif-else-regexp))
 574
 575
 576
 577 (defun hif-ifdef-to-endif ()
 578   "If positioned at #ifX or #else form, skip to corresponding #endif."
 579 ;  (message "hif-ifdef-to-endif at %d" (point)) (sit-for 1)
 580   (hif-find-next-relevant)
 581   (cond ((hif-looking-at-ifX)
 582          (hif-ifdef-to-endif) ; find endif of nested if
 583          (hif-ifdef-to-endif)) ; find outer endif or else
 584         ((hif-looking-at-else)
 585          (hif-ifdef-to-endif)) ; find endif following else
 586         ((hif-looking-at-endif)
 587          'done)
 588         (t
 589          (error "Mismatched #ifdef #endif pair"))))
 590
 591
 592 (defun hif-endif-to-ifdef ()
 593   "If positioned at #endif form, skip backward to corresponding #ifX."
 594 ;  (message "hif-endif-to-ifdef at %d" (point))
 595   (let ((start (point)))
 596     (hif-find-previous-relevant)
 597     (if (= start (point))
 598         (error "Mismatched #ifdef #endif pair")))
 599   (cond ((hif-looking-at-endif)
 600          (hif-endif-to-ifdef) ; find beginning of nested if
 601          (hif-endif-to-ifdef)) ; find beginning of outer if or else
 602         ((hif-looking-at-else)
 603          (hif-endif-to-ifdef))
 604         ((hif-looking-at-ifX)
 605          'done)
 606         (t)))                   ; never gets here
 607
 608
 609 (defun forward-ifdef (&optional arg)
 610   "Move point to beginning of line of the next ifdef-endif.
 611 With argument, do this that many times."
 612   (interactive "p")
 613   (or arg (setq arg 1))
 614   (if (< arg 0)
 615       (backward-ifdef (- arg)))
 616   (while (< 0 arg)
 617     (setq arg (- arg))
 618     (let ((start (point)))
 619       (if (not (hif-looking-at-ifX))
 620           (hif-find-next-relevant))
 621       (if (hif-looking-at-ifX)
 622           (hif-ifdef-to-endif)
 623         (goto-char start)
 624         (error "No following #ifdef")
 625         ))))
 626
 627
 628 (defun backward-ifdef (&optional arg)
 629   "Move point to beginning of the previous ifdef-endif.
 630 With argument, do this that many times."
 631   (interactive "p")
 632   (or arg (setq arg 1))
 633   (if (< arg 0)
 634       (forward-ifdef (- arg)))
 635   (while (< 0 arg)
 636     (setq arg (1- arg))
 637     (beginning-of-line)
 638     (let ((start (point)))
 639       (if (not (hif-looking-at-endif))
 640           (hif-find-previous-relevant))
 641       (if (hif-looking-at-endif)
 642           (hif-endif-to-ifdef)
 643         (goto-char start)
 644         (error "No previous #ifdef")))))
 645
 646
 647 (defun down-ifdef ()
 648   "Move point to beginning of nested ifdef or else-part."
 649     (interactive)
 650     (let ((start (point)))
 651       (hif-find-next-relevant)
 652       (if (or (hif-looking-at-ifX) (hif-looking-at-else))
 653           ()
 654         (goto-char start)
 655         (error "No following #ifdef"))))
 656
 657
 658 (defun up-ifdef ()
 659   "Move point to beginning of enclosing ifdef or else-part."
 660   (interactive)
 661   (beginning-of-line)
 662   (let ((start (point)))
 663     (if (not (hif-looking-at-endif))
 664         (hif-find-previous-relevant))
 665     (if (hif-looking-at-endif)
 666         (hif-endif-to-ifdef))
 667       (if (= start (point))
 668           (error "No previous #ifdef"))))
 669
 670 (defun next-ifdef (&optional arg)
 671   "Move to the beginning of the next #ifX, #else, or #endif.
 672 With argument, do this that many times."
 673   (interactive "p")
 674   (or arg (setq arg 1))
 675   (if (< arg 0)
 676       (previous-ifdef (- arg)))
 677   (while (< 0 arg)
 678     (setq arg (1- arg))
 679     (hif-find-next-relevant)
 680     (if (eolp)
 681         (progn
 682           (beginning-of-line)
 683           (error "No following #ifdefs, #elses, or #endifs")))))
 684
 685 (defun previous-ifdef (&optional arg)
 686   "Move to the beginning of the previous #ifX, #else, or #endif.
 687 With argument, do this that many times."
 688   (interactive "p")
 689   (or arg (setq arg 1))
 690   (if (< arg 0)
 691       (next-ifdef (- arg)))
 692   (while (< 0 arg)
 693     (setq arg (1- arg))
 694     (let ((start (point)))
 695       (hif-find-previous-relevant)
 696       (if (= start (point))
 697           (error "No previous #ifdefs, #elses, or #endifs")
 698         ))))
 699
 700
 701 ;===%%SF%% parsing (End)  ===
 702
 703
 704 ;===%%SF%% hide-ifdef-hiding (Start)  ===
 705
 706
 707 ;;; A range is a structure with four components:
 708 ;;; ELSE-P      True if there was an else clause for the ifdef.
 709 ;;; START       The start of the range. (beginning of line)
 710 ;;; ELSE        The else marker (beginning of line)
 711 ;;;                     Only valid if ELSE-P is true.
 712 ;;; END         The end of the range.  (beginning of line)
 713
 714 (defun hif-make-range (else-p start end &optional else)
 715   (list else-p start else end))
 716
 717 (defun hif-range-else-p (range)  (elt range 0))
 718 (defun hif-range-start (range) (elt range 1))
 719 (defun hif-range-else (range) (elt range 2))
 720 (defun hif-range-end (range) (elt range 3))
 721
 722
 723
 724 ;;; Find-Range
 725 ;;; The workhorse, it delimits the #if region.  Reasonably simple:
 726 ;;; Skip until an #else or #endif is found, remembering positions.  If
 727 ;;; an #else was found, skip some more, looking for the true #endif.
 728
 729 (defun hif-find-range ()
 730   "Returns a Range structure describing the current #if region.
 731 Point is left unchanged."
 732 ;  (message "hif-find-range at %d" (point))
 733   (save-excursion
 734     (beginning-of-line)
 735     (let ((start (point))
 736           (else-p nil)
 737           (else nil)
 738           (end nil))
 739       ;; Part one.  Look for either #endif or #else.
 740       ;; This loop-and-a-half dedicated to E. Dijkstra.
 741       (hif-find-next-relevant)
 742       (while (hif-looking-at-ifX)               ; Skip nested ifdef
 743         (hif-ifdef-to-endif)
 744         (hif-find-next-relevant))
 745       ;; Found either a #else or an #endif.
 746       (cond ((hif-looking-at-else)
 747              (setq else-p t)
 748              (setq else (point)))
 749             (t
 750              (setq end (point)) ; (save-excursion (end-of-line) (point))
 751              ))
 752       ;; If found #else, look for #endif.
 753       (if else-p
 754           (progn
 755             (hif-find-next-relevant)
 756             (while (hif-looking-at-ifX) ; Skip nested ifdef
 757               (hif-ifdef-to-endif)
 758               (hif-find-next-relevant))
 759             (if (hif-looking-at-else)
 760                 (error "Found two elses in a row?  Broken!"))
 761             (setq end (point))  ; (save-excursion (end-of-line) (point))
 762             ))
 763       (hif-make-range else-p start end else))))
 764
 765
 766 ;;; A bit slimy.
 767 ;;; NOTE:  If there's an #ifdef at the beginning of the file, we can't
 768 ;;; hide it.  There's no previous newline to replace.  If we added
 769 ;;; one, we'd throw off all the counts.  Feh.
 770
 771 (defun hif-hide-line (point)
 772   "Hide the line containing point.  Does nothing if `hide-ifdef-lines' is nil."
 773   (if hide-ifdef-lines
 774       (save-excursion
 775         (goto-char point)
 776         (let ((modp (buffer-modified-p)))
 777           (unwind-protect
 778               (progn
 779                 (beginning-of-line)
 780                 (if (not (= (point) 1))
 781                     (hide-ifdef-region (1- (point)) (point))))
 782             (set-buffer-modified-p modp))
 783           ))
 784     ))
 785
 786
 787 ;;;  Hif-Possibly-Hide
 788 ;;;  There are four cases.  The #ifX expression is "taken" if it
 789 ;;;  the hide-ifdef-evaluator returns T.  Presumably, this means the code
 790 ;;;  inside the #ifdef would be included when the program was
 791 ;;;  compiled.
 792 ;;;
 793 ;;;  Case 1:  #ifX taken, and there's an #else.
 794 ;;;     The #else part must be hidden.  The #if (then) part must be
 795 ;;;     processed for nested #ifX's.
 796 ;;;  Case 2:  #ifX taken, and there's no #else.
 797 ;;;     The #if part must be processed for nested #ifX's.
 798 ;;;  Case 3:  #ifX not taken, and there's an #else.
 799 ;;;     The #if part must be hidden.  The #else part must be processed
 800 ;;;     for nested #ifs.
 801 ;;;  Case 4:  #ifX not taken, and there's no #else.
 802 ;;;     The #ifX part must be hidden.
 803 ;;;
 804 ;;;  Further processing is done by narrowing to the relevant region
 805 ;;;  and just recursively calling hide-ifdef-guts.
 806 ;;;
 807 ;;;  When hif-possibly-hide returns, point is at the end of the
 808 ;;;  possibly-hidden range.
 809
 810 (defun hif-recurse-on (start end)
 811   "Call `hide-ifdef-guts' after narrowing to end of START line and END line."
 812   (save-excursion
 813     (save-restriction
 814       (goto-char start)
 815       (end-of-line)
 816       (narrow-to-region (point) end)
 817       (hide-ifdef-guts))))
 818
 819 (defun hif-possibly-hide ()
 820   "Called at #ifX expression, this hides those parts that should be
 821 hidden, according to judgement of `hide-ifdef-evaluator'."
 822 ;  (message "hif-possibly-hide") (sit-for 1)
 823     (let ((test (hif-canonicalize))
 824           (range (hif-find-range)))
 825 ;      (message "test = %s" test) (sit-for 1)
 826
 827       (hif-hide-line (hif-range-end range))
 828       (if (funcall hide-ifdef-evaluator test)
 829           (cond ((hif-range-else-p range) ; case 1
 830                  (hif-hide-line (hif-range-else range))
 831                  (hide-ifdef-region (hif-range-else range)
 832                                     (1- (hif-range-end range)))
 833                  (hif-recurse-on (hif-range-start range)
 834                                  (hif-range-else range)))
 835                 (t ; case 2
 836                  (hif-recurse-on (hif-range-start range)
 837                                  (hif-range-end range))))
 838         (cond ((hif-range-else-p range) ; case 3
 839                (hif-hide-line (hif-range-else range))
 840                (hide-ifdef-region (hif-range-start range)
 841                                   (1- (hif-range-else range)))
 842                (hif-recurse-on (hif-range-else range)
 843                                (hif-range-end range)))
 844               (t ; case 4
 845                (hide-ifdef-region (point)
 846                                   (1- (hif-range-end range))))
 847               ))
 848       (hif-hide-line (hif-range-start range))   ; Always hide start.
 849       (goto-char (hif-range-end range))
 850       (end-of-line)
 851       ))
 852
 853
 854
 855 (defun hide-ifdef-guts ()
 856   "Does the work of `hide-ifdefs', except for the work that's pointless
 857 to redo on a recursive entry."
 858 ;  (message "hide-ifdef-guts")
 859   (save-excursion
 860     (goto-char (point-min))
 861     (while (hif-find-any-ifX)
 862       (hif-possibly-hide))))
 863
 864 ;===%%SF%% hide-ifdef-hiding (End)  ===
 865
 866
 867 ;===%%SF%% exports (Start)  ===
 868
 869 ;;;###autoload
 870 (defvar hide-ifdef-initially nil
 871   "*Non-nil if `hide-ifdefs' should be called when Hide-Ifdef mode
 872 is first activated.")
 873
 874 (defvar hide-ifdef-hiding nil
 875   "Non-nil if text might be hidden.")
 876
 877 ;;;###autoload
 878 (defvar hide-ifdef-read-only nil
 879   "*Set to non-nil if you want buffer to be read-only while hiding text.")
 880
 881 (defvar hif-outside-read-only nil
 882   "Internal variable.  Saves the value of `buffer-read-only' while hiding.")
 883
 884 ;;;###autoload
 885 (defvar hide-ifdef-lines nil
 886   "*Set to t if you don't want to see the #ifX, #else, and #endif lines.")
 887
 888 (defun hide-ifdef-toggle-read-only ()
 889   "Toggle hide-ifdef-read-only."
 890   (interactive)
 891   (setq hide-ifdef-read-only (not hide-ifdef-read-only))
 892   (message "Hide-Read-Only %s"
 893            (if hide-ifdef-read-only "ON" "OFF"))
 894   (if hide-ifdef-hiding
 895       (setq buffer-read-only (or hide-ifdef-read-only hif-outside-read-only)))
 896   (hif-update-mode-line))
 897
 898 (defun hide-ifdef-toggle-outside-read-only ()
 899   "Replacement for `toggle-read-only' within Hide Ifdef mode."
 900   (interactive)
 901   (setq hif-outside-read-only (not hif-outside-read-only))
 902   (message "Read only %s"
 903            (if hif-outside-read-only "ON" "OFF"))
 904   (setq buffer-read-only
 905         (or (and hide-ifdef-hiding hide-ifdef-read-only)
 906             hif-outside-read-only)
 907         )
 908   (hif-update-mode-line))
 909
 910
 911 (defun hide-ifdef-define (var)
 912   "Define a VAR so that #ifdef VAR would be included."
 913   (interactive "SDefine what? ")
 914   (hif-set-var var 1)
 915   (if hide-ifdef-hiding (hide-ifdefs)))
 916
 917 (defun hide-ifdef-undef (var)
 918   "Undefine a VAR so that #ifdef VAR would not be included."
 919   (interactive "SUndefine what? ")
 920   (hif-set-var var nil)
 921   (if hide-ifdef-hiding (hide-ifdefs)))
 922
 923
 924 (defun hide-ifdefs ()
 925   "Hide the contents of some #ifdefs.
 926 Assume that defined symbols have been added to `hide-ifdef-env'.
 927 The text hidden is the text that would not be included by the C
 928 preprocessor if it were given the file with those symbols defined.
 929
 930 Turn off hiding by calling `show-ifdefs'."
 931
 932   (interactive)
 933   (message "Hiding...")
 934   (if (not hide-ifdef-mode)
 935       (hide-ifdef-mode 1)) ; turn on hide-ifdef-mode
 936   (if hide-ifdef-hiding
 937       (show-ifdefs))                    ; Otherwise, deep confusion.
 938   (let ((inhibit-read-only t))
 939     (setq selective-display t)
 940     (setq hide-ifdef-hiding t)
 941     (hide-ifdef-guts))
 942   (setq buffer-read-only (or hide-ifdef-read-only hif-outside-read-only))
 943   (message "Hiding done"))
 944
 945
 946 (defun show-ifdefs ()
 947   "Cancel the effects of `hide-ifdef'.  The contents of all #ifdefs is shown."
 948   (interactive)
 949   (setq buffer-read-only hif-outside-read-only)
 950   (setq selective-display nil)  ; defaults
 951   (let ((inhibit-read-only t))
 952     (hif-show-all))
 953   (setq hide-ifdef-hiding nil))
 954
 955
 956 (defun hif-find-ifdef-block ()
 957   "Utility for hide and show `ifdef-block'.
 958 Set top and bottom of ifdef block."
 959   (let (max-bottom)
 960   (save-excursion
 961     (beginning-of-line)
 962     (if (not (or (hif-looking-at-else) (hif-looking-at-ifX)))
 963         (up-ifdef))
 964     (setq top (point))
 965     (hif-ifdef-to-endif)
 966     (setq max-bottom (1- (point))))
 967   (save-excursion
 968     (beginning-of-line)
 969     (if (not (hif-looking-at-endif))
 970         (hif-find-next-relevant))
 971     (while (hif-looking-at-ifX)
 972       (hif-ifdef-to-endif)
 973       (hif-find-next-relevant))
 974     (setq bottom (min max-bottom (1- (point))))))
 975   )
 976
 977
 978 (defun hide-ifdef-block ()
 979   "Hide the ifdef block (true or false part) enclosing or before the cursor."
 980   (interactive)
 981   (if (not hide-ifdef-mode)
 982       (hide-ifdef-mode 1))
 983   (setq selective-display t)
 984   (let (top bottom (inhibit-read-only t))
 985     (hif-find-ifdef-block) ; set top and bottom - dynamic scoping
 986     (hide-ifdef-region top bottom)
 987     (if hide-ifdef-lines
 988         (progn
 989           (hif-hide-line top)
 990           (hif-hide-line (1+ bottom))))
 991     (setq hide-ifdef-hiding t))
 992   (setq buffer-read-only (or hide-ifdef-read-only hif-outside-read-only)))
 993
 994
 995 (defun show-ifdef-block ()
 996   "Show the ifdef block (true or false part) enclosing or before the cursor."
 997   (interactive)
 998   (let ((inhibit-read-only t))
 999     (if hide-ifdef-lines
1000         (save-excursion
1001           (beginning-of-line)
1002           (hif-show-ifdef-region (1- (point)) (progn (end-of-line) (point))))
1003
1004       (let (top bottom)
1005         (hif-find-ifdef-block)
1006         (hif-show-ifdef-region (1- top) bottom)))))
1007
1008
1009 ;;;  definition alist support
1010
1011 (defvar hide-ifdef-define-alist nil
1012   "A global assoc list of pre-defined symbol lists")
1013
1014 (defun hif-compress-define-list (env)
1015   "Compress the define list ENV into a list of defined symbols only."
1016   (let ((defs (mapcar '(lambda (arg)
1017                          (if (hif-lookup (car arg)) (car arg)))
1018                       env))
1019         (new-defs nil))
1020     (while defs
1021       (if (car defs)
1022           (setq new-defs (cons (car defs) new-defs)))
1023       (setq defs (cdr defs)))
1024     new-defs))
1025
1026 (defun hide-ifdef-set-define-alist (name)
1027   "Set the association for NAME to `hide-ifdef-env'."
1028   (interactive "SSet define list: ")
1029   (setq hide-ifdef-define-alist
1030         (cons (cons name (hif-compress-define-list hide-ifdef-env))
1031               hide-ifdef-define-alist)))
1032
1033 (defun hide-ifdef-use-define-alist (name)
1034   "Set `hide-ifdef-env' to the define list specified by NAME."
1035   (interactive "SUse define list: ")
1036   (let ((define-list (assoc name hide-ifdef-define-alist)))
1037     (if define-list
1038         (setq hide-ifdef-env
1039               (mapcar '(lambda (arg) (cons arg t))
1040                       (cdr define-list)))
1041       (error "No define list for %s" name))
1042     (if hide-ifdef-hiding (hide-ifdefs))))
1043
1044 ;;; hideif.el ends here
1045